1. Field of the Invention
The present invention is related to a rotor device capable of dissipating heat and resisting foreign objects and particularly to a rotor assembly, which can remove heat generated from running of the rotor and prevent the foreign objects from falling into the rotor device.
2. Brief Description of the Related Art
Referring to FIG. 1, a conventional rotor assembly of a fan motor includes a shield case 11 and a hub 12, which is attached to the outer surface of the shield case 11. The shield case 11 has a top wall 111 and a lateral wall 112, which is integral with and extends downward from the top wall 111. The top wall provides a plurality of through holes 113. The hub 12 has a closed wall adjacent to the top wall 111 and a hub wall 122 adjacent to the lateral wall 112 and integral with the closed wall 121. Hub holes 123 are provided to align with the through holes 113 so that passages are formed to allow the fluid passing through. When a rotor 13 and a stator 14, which are mounted in the shield case 11 and the hub 12, rotate to generate heat, temperature of the fluid in the shield case 11 and the hub 12 rises and flows outward via the through holes 113 and the hub holes 123. Hence, the heat in the shield case 11 and the hub 12 can be dissipated to enhance the performance of the rotor 13 and the stator 14 and extend life span thereof.
Further, the shield case 11 is made of metal and the hub is made of plastics.
However, the preceding rotor assembly has a problem that foreign objects easily enter or fall into the shield case 11 through the hub hole 123 and the through holes 113 directly to affect internal operation.
Further, the shield case 11 can transmit heat generated from the rotor 13 and stator 14 but the plastic hub 12 provides much lower effect of heat transmission than the metal shield case 11, that is, the heat conductivity of the hub 12 is much lower than the shield case 11. Thus, the heat through the shield case 11 is incapable of being dissipated outward via the hub 12 effectively.